Controlled data network error recovery

Abstract

A method, a system and network nodes use an indication of possible duplicates of units, so that these units can be handled differently than other units. The unit is indicated to be a possible duplicate to the entity to which it is resent because no response was received from the entity it was sent to.

What is claimed is: 
     
       1. A method comprising:
 sending a unit to a first receiving entity in a telecommunications system; 
 in the event that no response is received from the first receiving entity, resending the unit to a second receiving entity with an indication of a possible duplicate, the indication of a possible duplicate indicating that the unit was resent because no response was received; and 
 sending a message to the second receiving entity to release or delete the unit depending on a subsequently determined status of the first receiving entity. 
 
     
     
       2. The method of  claim 1 , further comprising also indicating a sending entity when the unit is resent with the indication of a possible duplicate. 
     
     
       3. The method of  claim 1 , further comprising:
 upon resending the unit to the second receiving entity; 
 causing the second receiving entity to check, only in response to the indication of a possible duplicate, whether the unit is a duplicate. 
 
     
     
       4. A method comprising:
 receiving in a first receiving entity a unit including an indication of possible duplicate that indicates a reason for resending the unit; 
 comparing sequence numbers of received units in order to find out whether the unit is a duplicate only in response to the indicated reason being that the unit was resent because no response was received; 
 storing the unit upon determining that the unit is a duplicate; and 
 waiting for instructions to release or delete the unit while transmitting other units normally. 
 
     
     
       5. A network node comprising:
 a memory; and 
 a processor operatively connected to the memory and configured to, in response the absence of receiving a response from a first entity to which a unit was sent:
 resend the unit to a second receiving entity with an indication of a possible duplicate, the indication of a possible duplicate indicating that the unit was resent because no response was received from the first entity; and 
 send a message to the second receiving entity to release or delete the unit depending on a subsequently determined status of the first receiving entity. 
 
 
     
     
       6. The network node of  claim 5 , wherein the processor is further configured to indicate the sending entity when sending the indication of a possible duplicate. 
     
     
       7. The network node of  claim 5 , further comprising a memory comprising a data structure containing a priority list of entities to which units may be sent, and wherein the processor is further configured to resend the unit to the entity having the next lowest priority.